Simplify the following expression. $ (4 + (8 - 9 \times 8)) \times 7 $
Answer: $ = (4 + (8 - 72)) \times 7 $ $ = (4 + (-64)) \times 7 $ $ = (4 - 64) \times 7 $ $ = (-60) \times 7 $ $ = -60 \times 7 $ $ = -420 $